| 摘要 |
PURPOSE:To stabilize a discharge by forming the shape of a cathode substantially in a U-shape, always cooling the discharge of the cathode to largely improve the cooling effect of the cathode, and enhancing the maximum injection power until it is transferred to an arc. CONSTITUTION:Each cathode 11 is formed of a plurality, for example, 2 of ends 11A of rod shape formed substantially in U shape projected to an anode 9 and a discharge 11B parallel to a gas flowing direction. Stable resistors 15 are connected to the end 11A of the two ends 11A at the upstream side with respect to the gas flowing direction. The U shape of the cathode 11 includes not only the U shape but also a V shape. Thus, the discharge 11B and the bent 11C of the end 11A at the downstream side become a discharge starter, and the bent 11C of the starter is cooled. Accordingly, it is not overheated, but suppressed to be transferred to an arc discharge. Thus, the maximum injection power to the transfer of the arc is enhanced to stabilize the discharge. |
